Henry Fielding, born in Somerset in 1707 and educated at Eton College, was a true son of London. The city became the landscape of his imagination and the centre of his multifarious activities. It is also the vibrant setting for the life and adventures of Jonathan Wild. Fielding was a dramatist long before he ever became a novelist. For eight years he wrote comedies, farces and burlesques, some of them considered to be notably lewd or "loose", and was granted the title of "the English Molière".

In less than three years, between 1730 and 1732, he wrote no less than 13 plays. Even by the copious standards of the day it was an astonishing production. In true urban fashion he also earned his living as a journalist and a pamphleteer. He wrote pamphlets entitled "An Attempt Towards a Natural History of the Hanover Rat", a satire on the use of Hanoverian mercenaries, and "A Dialogue between the Devil, the Pope and the Pretender condemning the Stuart cause". He also edited newspapers and created a journalistic character, Hercules Vinegar, who commented on the topics of the day. His theatrical and journalistic gifts then came together in Jonathan Wild - or to give it its full title on its first appearance in 1743, The Life of Mr Jonathan Wild the Great.

It comprised the third volume of Fielding's scattered writings known as Miscellanies, largely devoted to the themes of grandiose ambition and false greatness. He seems to have composed Jonathan Wild in the spring and summer of 1742, just after completing Joseph Andrews and immediately following the resignation of Robert Walpole in February of that year - Walpole being the prime minister whose lavish use of bribes and patronage, and whose engineering of plots and cabals, rendered him the epitome of political corruption in the period.

Walpole himself enters the plot of Jonathan Wild only obliquely, but the text is indebted to his example of villainy and chicanery in high places. Fielding does not make the point so deliberately as John Gay in The Beggar's Opera, staged some 15 years before, but there is a clear resemblance between the sins of high life and of low life. Why should one deserve a peerage, and the other a gallows?

But Jonathan Wild is not a piece of contemporary political analysis, or even a social history. It is a work in which fact and fiction become strangely merged. As Fielding states in his preface to the Miscellanies, "it is not a very faithful portrait of Jonathan Wild himself". He goes on to confess that "my narrative is rather of such actions which he might have performed, or would, or should have performed than what he really did". But if it is not a biography, it can hardly be classified as a novel. Some of the events related are indeed authentic, and the speeches as well as the maxims of Wild are not really appropriate in a fictional context. The book is essentially an exercise in irony, a philosophical satire that anticipates Johnson's Rasselas and Voltaire's Candide.

Wild was already a famous London figure before Fielding transmuted him in print. Daniel Defoe had written a book on his exploits, and there were other brief lives of dubious authenticity. Wild's urban career really began as a "thief-taker", but this was cover for his more profitable activity as a fence of stolen goods. He would direct his criminal associates towards a target, take the proceeds of the theft from them, and then at a price, return the same goods to the unfortunate victim. From his "office" in Cripplegate he would miraculously "find" important items. He would often betray his less successful or less complaisant confederates to the authorities, and thus gained a reputation as an honest member of the common wealth. He posed as a useful citizen, when in fact he was one of the most ruthless and violent men of a ruthless and violent age.

Fielding was not in any case unacquainted with this world. He had been arrested and imprisoned for debt, and the scenes set in Newgate are written with the full force of personal acquaintance. But he also knew the other face of the law, and seven years after writing Jonathan Wild, he was appointed as a magistrate for Middlesex with his court at Bow Street. It was he who set up a plan for two full-time police officers, who later became known as the "Bow Street Runners".

He knew of what he wrote. He knew London to be a wilderness. It was, as he put it in another context, "a vast wood or forest in which the thief may harbour with as great security as wild beasts do in the deserts of Arabia and Africa". Wild, and such associates as Fierce, Fireblood and Molly Straddle, are the pitiless creatures of this forest which prey upon their victims.

But although Jonathan Wild derives in part from the rogue literature and criminal biographies of previous centuries, it is much more than that. It is an anti-epic and, as Fielding's prefatory material suggests, a parody of greatness in all its aspects. He detested the glamour and fame attached to "greatness", whether in the form of Alexander the Great or Julius Caesar. The soubriquet of "great man" disgusted him. That is why he implicitly compared Jonathan Wild to Robert Walpole, and why throughout this text there is a constant undermining of the idea and ideal of greatness in all its forms.

As he remarks in the Miscellanies preface, "Pride, Ostentation, Insolence, Cruelty, and every kind of Villany, are often construed into True Greatness of Mind." This bombast, this "false sublime", is unfavourably compared to "goodness", of which the Heartfrees in this book are the symbolic representatives. In that sense Jonathan Wild is an allegory in which Wild himself is seen as a representative of evil, an example of selfishness and wanton appetite opposed to good nature and benevolence. These are the forces that war for the soul of the world.

The Life of Mr Jonathan Wild the Great is a succinct study of a mighty theme, yet it is one that employs humour and satire as a way of conveying its moral. Note, as an example, the ending of the story when Wild is paraded on the gallows as the halter is placed around his neck - "Wild, in the midst of the shower of stones, etc, which played upon him, applied his hands to the parson's pocket, and emptied it of his bottle-screw, which he carried out of the world in his hand". It is the mark of literary genius to use the smallest detail to subvert the greatest moment. It is also the pervasive method of this book.